Click on possible answers in the right column to hide/show them on the graph. You can also hover over any line to see current value at that time. Graphs will begin to show data one hour after the question has been open. The Historical Trend chart does not display all prices ever reached since it is only updated at discrete time intervals, (hourly/daily/weekly, depending on the date range).
These contracts are priced in basis points. One basis point is 1/100th of a percent. For example, on 2014-08-13, the effective funds rate was .09%, or 9 basis points. This would equal a contract price of $9.00.
This question is asking about the effective rate, not the target rate.
The daily effective federal funds rate is a volume-weighted average of rates on trades arranged by major brokers. The effective rate is calculated by the Federal Reserve Bank of New York using data provided by the brokers and is subject to revision.
We'll use the 'Daily' column in the official numbers published at the above URL. Each answer will be cashed out after that date's number is published.
If there is no published number for a given answer's date, then the next published date's number will be used to cash out the answer. (For example, the FOMC did not publish a number for 2014-09-01, but did publish one for 2014-09-02, so I would use the 2014-09-02 rate number to cash out the 2014-09-01 answer.)